Emissions reduction pledges made ahead of the Paris summit will fail to keep global temperature rise below the 2ºC level scientists believe is necessary to avoid dangerous climate change, according to a study.
The research, which updates earlier estimates, assessed the intended national determined contributions (INDCs) that 46 countries had submitted to the UNFCCC by 20 July 2015.
These include China, the 28 EU member states, Japan, Mexico and the US, and account for 58% of global greenhouse-gas emissions. The researchers from the Grantham Research Institute on Climate Change and the Environment at the London School of Economics and Political Science found the pledges would lead to annual global emissions in 2030 of 56.9 to 59.1 billion tonnes of carbon dioxide equivalent (tCO2eq).
Although this much less than the current business-as-usual pathway, on which emissions reach 68 billion tCO2eq by 2030, it is much higher than the 36 billion tCO2eq that UNEP has calculated would be consistent with a 50% to 66% chance of avoiding a rise in global average temperature of more than 2ºC above the pre-industrial level.
The pledges also fall well short of the target of 42 billion tCO2eq for a pathway that avoids the temperature limit by using technologies that create “negative emissions”, such as bioenergy with carbon capture and storage.
The authors, Rodney Boyd, Joe Cranston Turner and Bob Ward, say countries need to find further credible ways over the next few months of achieving bigger emissions reductions, which they can include in their INDCs. They are also calling for any agreement at COP21 in Paris to include a mechanism to allow countries to review their efforts and to find ways of ramping up the ambition of their emissions reductions by 2030 and beyond.
